Add UI tests for Riverpod providers

[sixtusagbo]

PR Description

This pull request introduces UI tests to verify the behavior of our application's UI elements in conjunction when different Riverpod states are injected. I await the review of my approach and I patiently wait for the maintainers' feedback.

Related Issues

• Related Issue #118

Checklist

• [x] I have gone through the contributing guide
• [x] I have updated my branch and synced it with project main branch before making this PR
• [x] I have run the tests (flutter test) and all tests are passing

Added/updated tests?

We encourage you to add relevant test cases.

• [x] Yes
• [ ] No, and this is why: please replace this line with details on why tests have not been included

[animator]

Thanks for the PR @sixtusagbo 🚀 Please continue the good work and send across more such PRs testing other providers and screens.